1. Technical Field
The present disclosure relates to a method for simultaneous playback of audio tracks from a plurality of digital devices.
The disclosure also relates to a system for simultaneous playback of audio tracks from a plurality of digital transceiver devices.
The disclosure also relates to digital devices such as mobile cell phones and the following description is given with particular reference to this field of application.
2. Description of the Related Art
In recent years, considerable interest has been focused on techniques for synchronizing digital audio contents in systems with local communication networks, in which wireless apparatus, mobile phones, smartphones and other high-speed digital devices simultaneously play the same audio content.
In this context in which the same audio content is simultaneously played by two or more mobile phones, two requirements are known to be imposed:                synchronized playback, for the audio content to be played at the same time on all the mobile phones;        tuned playback, which means that the audio content must be played at the same frequency to prevent echoes during audio content playback on all the mobile phones.        
Digital devices are known to have a specific sampling frequency other than the sampling frequency of other similar digital devices.
Therefore, during simultaneous playback of the same audio track, the difference between the sampling frequencies of the digital devices is perceived by a listener, as an untuned sound, e.g., a sound with echo.
Echo is substantially the resultant of the individual playbacks, as schematically shown in FIG. 1, in the case of two individual playbacks with different sampling frequencies.
A solution to the above drawbacks is based on processing of the audio track received by the individual device and stored as a digital signal. Such processing uses complex algorithms for controlling the buffer of the stored digital signal and aligning audio playback buffers of two digital devices.
A second solution is disclosed in the US patent application No. US2003/0198257 by Sullivan et al., which teaches the use of graphical user interfaces for manually synchronizing the playback of a received digital audio signal.
Another solution is disclosed in the US patent application No. US2008/0225826 by Gentric, in which the playback of an audio broadcast over a network with a plurality of digital devices, is synchronized by selecting a device for reception and simultaneously preventing the other unselected devices from receiving and playing the audio broadcast through the creation of suitable echoes.
While these solutions are satisfactory in certain respects, they still have drawbacks mainly associated by their complex implementation.